A Bizarre Physics Law Is Making Superfluid Helium Behave Like an Actual Black Hole

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Of all the laws of physics, this is arguably one of the strangest - scientists have discovered that the forces controlling the behaviour of a black hole's event horizon are also at play in superfluid helium, an extraordinary liquid that flows without friction.

This entanglement area law has now been observed at both the vast scale of black holes and the atomic scale of cold helium, and could be the key to finally establishing the long sought-after quantum theory of gravity - the solution to one of the deepest problems in theoretical physics today.

Thanks to entropy, the arrow of time only ever moves forward, and since the moment of the Big Bang, the Universe and everything in it has been gradually moving towards heightened chaos.

In the 1970s, Hawking and fellow theoretical physicist Jacob Bekenstein discovered that when matter is unfortunate enough to wander too close to the event horizon of a black hole and fall in, the information that's then added to the black hole - a form of entropy - only increases as fast as the black hole's surface area increases.

When Del Maestro and his colleagues uploaded their simulation to two supercomputers, they were able to run separate simulations of 64 helium atoms as they transitioned to a superfluid.

Within this superfluid, they established two hypothetical sections - a sphere of superfluid, and the superfluid that surrounded it - and kept track of the amount of entangled quantum information shared between them as the sphere was increased.

If you think back to the black holes, this entangled quantum information is analogous to the information falling over the event horizon to increase the entropy inside. 

Just like what Hawking and Bekenstein had found, they watched as the amount of entangled quantum information shared between two regions the superfluid was determined by the surface area of the sphere, but not its volume.

"Like a holograph, it seems that a three-dimensional volume of space is entirely encoded on its two-dimensional surface. Just like a black hole," the team describes.

According to Emily Conover at Science News, while the phenomenon had previously been predicted in superfluids, this is the first time that it has been demonstrated in simulations of a naturally occurring state of matter.

And that's important, because the phenomenon of quantum entanglement does not gel with the standard model of physics, and made Einstein himself deeply uncomfortable, but it's here to stay, and we need better ways of studying it.

"Entanglement is non-classical information shared between parts of a quantum state. [It's] the characteristic trait of quantum mechanics that is most foreign to our classical reality," Del Maestro says in a press statement.

"Our classical theory of gravity relies on knowing exactly the shape or geometry of space-time."

As theories that explain the behaviour of all the vast and tiny things in our Universe, Einstein's theory of relativity and quantum mechanics don't mesh, and one of the most significant problems in modern physics is finding a way to combine the two into a universal quantum theory of gravity.

Maybe finally being able to watch the strangeness of quantum entanglement in a naturally occurring state of matter will get us closer to that goal.

The research was published in Nature Physics. Source: Science Alert